The present invention, in some embodiments thereof, relates to applied materials and more particularly, but not exclusively, to vapor deposition techniques utilizing biomolecules such as peptides, and applications thereof.
Vapor deposition is a general term used to describe any of a variety of methods for depositing a thin film of a material by the condensation, reaction or conversion of a vaporized form of the material, or a precursor thereof, onto the surface of various substrates. Thin films are thin material layers ranging from fractions of a nanometer to several micrometers in thickness. Vapor deposition is used to form a coat (film) of the deposited material so as to alter the mechanical (such as wear properties, lubrication and friction), electrical (such as semi-conductivity), electrochemical (such as electrode efficiency), thermal (such as heat conductivity), optical (such as light reflectivity), chemical (such as corrosion resistance, chemical compatibility, wettability and hydrophobicity), biological (such as anti-microbial and cells adhesion) of the substrates. Vapor deposition is also used to form free-standing bodies, wherein the substrate support is removed, such as films and fibers and composite materials.
Vapor deposition processes typically belong to one of two categories of vapor deposition processes: physical vapor deposition (PVD) and/or chemical vapor deposition (CVD), both of which are usually performed in a vacuum chamber.
In PVD, the coating method involves mainly physical processes such as, for example, elevated temperatures, high vacuum or plasma sputter bombardment, rather than a chemical reaction of a vaporized material at the surface to be coated, as in chemical vapor deposition (CVD). Evaporative deposition is a PVD process in which the material to be deposited is heated to a high vapor pressure by electrically resistive heating in “high” vacuum. Electron beam deposition is a PVD process in which the material to be deposited is heated to a high vapor pressure by electron bombardment in “high” vacuum. Sputter deposition is a PVD process in which a glow plasma discharge (usually localized around the “target” by a magnet) bombards the material sputtering some of it away as a vapor. Cathodic arc deposition is a PVD process in which a high power arc is directed at a material blasts some of it away into a vapor. Pulsed laser deposition is a PVD process in which a high power laser ablates material into a vapor.
PVD methods produce even and homogeneous coating of entire objects in a relatively straight-forward procedure, however, the physical conditions to which the subject and the coating material are subjected-to are rather harsh, and therefore may harm some heat sensitive target materials.